Medium access control-high speed

ABSTRACT

A medium access control-high speed (MAC-hs) comprises a hybrid automatic repeat request (H-ARQ) device configured to receive data blocks over a wideband-code division multiple access (W-CDMA) high speed-downlink shared channel (HS-DSCH). The H-ARQ device generates an acknowledgement (ACK) or negative acknowledgement (NACK) for each said data block received. Each received data block having a transmission sequence number. The H-ARQ device receives a new transmission instead of a pending retransmission at any time. At least one reordering device has an input configured to receive an output of the H-ARQ device and the at least one reordering device configured to reorder the received data blocks based on each received data block&#39;s transmission sequence number (TSN). Received data blocks are immediately forwarded for processing for higher layers when the received data blocks are received in sequence.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.10/270,822 filed Oct. 15, 2002 which claims priority from U.S.Provisional Patent Application No. 60/343,661 filed Oct. 19, 2001, allof which are incorporated by reference as if fully set forth.

BACKGROUND

The present invention is related to MAC architecture in a wirelesscommunication system where Hybrid Automatic Repeat Request (H-ARQ)techniques are applied.

A block diagram of the UMTS Terrestrial Radio Access Network (UTRAN)MAC-hs layer architecture is illustrated in FIG. 1, and a block diagramof the user equipment (UE) MAC hs architecture is shown in FIG. 2. TheUTRAN MAC-hs 30 shown in FIG. 1 comprises a Transport Format Combination(TFC) selection entity 31, a scheduling device 32, a plurality of H-ARQprocessors 33 a, 33 b and a flow controller 34.

The UE MAC-hs 40 comprises an H-ARQ processor 41. As will be explainedin further detail herinafter, with reference to both FIGS. 1 and 2, theH-ARQ processors 33 a, 33 b in the UTRAN MAC-hs 30 and the H-ARQprocessor 41 in the UE MAC-hs 40 work together to process blocks ofdata.

The H-ARQ processors 33 a, 33 b in the UTRAN MAC-hs 30 handle all of thetasks that are required for H-ARQ to generate transmissions andretransmissions for any transmission that is in error. The H-ARQprocessor 41 in the UE MAC-hs 40 is responsible for generatingacknowledgements (ACKs) to indicate a successful transmission andnegative acknowledgements (NACKs) in the case of failed transmissions.The H-ARQ processors 33 a, 33 b and 41 process sequential data streamsfor each user data flow. Blocks of data received on each user data floware sequentially assigned to H-ARQ processors 33 a, 33 b. Each H-ARQprocessor 33 a, 33 b initiates a transmission, and in the case of anerror, the H-ARQ processor 41 requests a retransmission. On subsequenttransmissions, the modulation and coding rate may be changed in order toensure a successful transmission. The H-ARQ processor 41 in the UEMAC-hs 40 may combine the soft information from the originaltransmission and any subsequent retransmissions. The data to beretransmitted and any new transmissions to the UE are forwarded to thescheduling device 32.

The scheduling device 32, coupled between the H-ARQ processors 33 a, 33b and the TFC selector 31, functions as radio resource manager anddetermines transmission latency in order to support the required QoS.Based on the outputs of the H-ARQ processors 33 a, 33 b and the priorityof new data being transmitted, the scheduling device 32 forwards thedata to the TFC selection entity 31.

The TFC selection entity 31, coupled to the scheduling device 32,receives the data to be transmitted and selects an appropriate dynamictransport format for the data to be transmitted. With respect to H-ARQtransmissions and retransmissions, the TFC selection entity 31determines modulation and coding.

Data streams are processed sequentially, and each data block isprocessed until successful transmission is achieved or the transmissionfails and the data is discarded. Retransmissions signaled by the H-ARQprocess take precedence over any new data to be transmitted. Each H-ARQprocessor 33 a, 33 b performs transmissions and retransmissions untilthe data block transmission is determined successful or failed. Usingthis scheme, higher priority data transmissions may be delayed whilelower priority data retransmissions are processed until success orfailure is determined.

UE connections require support of several independent traffic controlsignaling channels. Each of these channels has QoS requirements, whichinclude guaranteed and/or acceptable transmission latency levels. Sincethe H-ARQ processing is taken into account prior to scheduling, it isnot possible for higher priority data to supercede lower priority dataretransmissions. Therefore, the transmission latency QoS requirementsfor high priority data transmissions may not be achievable when lowpriority data transmissions have been previously assigned to H-ARQprocessors 33 a, 33 b.

Since retransmissions are combined with previous transmissions in theH-ARQ process, it is possible that if the first transmissions aresufficiently corrupted, subsequent retransmissions will not achievesuccessful transmission. In this case since transmissions can not bereinitiated as new transmissions from the scheduling entity 32, data isdiscarded.

Accordingly, there exists a need for an improved MAC-hs architectureboth in the UTRAN and UE that allows for higher priority transmissionsto supercede lower priority transmissions and for the ability toreinitiate transmissions at any time.

SUMMARY

A medium access control-high speed (MAC-hs) comprises a hybrid automaticrepeat request (H-ARQ) device configured to receive data blocks over awideband-code division multiple access (W-CDMA) high speed-downlinkshared channel (HS-DSCH). The H-ARQ device generates an acknowledgement(ACK) or negative acknowledgement (NACK) for each said data blockreceived. Each received data block having a transmission sequencenumber. The H-ARQ device receives a new transmission instead of apending retransmission at any time. At least one reordering device hasan input configured to receive an output of the H-ARQ device and the atleast one reordering device configured to reorder the received datablocks based on each received data block's transmission sequence number(TSN). Received data blocks are immediately forwarded for processing forhigher layers when the received data blocks are received in sequence.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a prior art UTRAN MAC-hs.

FIG. 2 is a prior art UE MAC-hs.

FIG. 3 is a block diagram of a UTRAN MAC-hs in accordance with thepreferred embodiment of the present invention.

FIG. 4 is a block diagram of a UE MAC-hs in accordance with thepreferred embodiment of the present invention.

FIG. 5 is a flow diagram of a procedure for permitting higher prioritytransmissions to interrupt lower priority transmissions to achievetransmission seven zero latency requirements.

FIG. 6 is a flow diagram of a procedure to re-initiate failedtransmissions to achieve Block Error Rate requirements.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The preferred embodiments will be described with reference to thedrawing figures where like numerals represent like elements throughout.

FIG. 3 is a block diagram of the UTRAN MAC-hs 50, preferably located atthe Node B, in accordance with the preferred embodiment of the presentinvention. The UTRAN MAC-hs 50 comprises a TFC selector 51, a pluralityof H-ARQ entities 52 a, 52 b, a scheduling and prioritization entity 53,a priority class and TSN setting entity 54 and a flow controller 55. Aswill be explained in detail, the components of the UTRAN MAC-hs 50 arecoupled together in a novel manner, which facilitates proper schedulingprioritization for greater ability to achieve transmission latencyrequirements and the ability to reinitiate transmissions at any time toreduce transmission errors within the UTRAN MAC-hs 50 (shown in FIG. 3)and UE MAC-hs 60 (shown in FIG. 4).

Similar to the prior art flow controller 34 discussed hereinbefore, theflow controller 55 of the present invention shown in FIG. 3, and,coupled to the MAC-c/sh of the RNC (not shown) and the priority classand TSN setting entity 54, provides a controlled data flow between theNode B and the RNC, taking the transmission capabilities of the airinterface into account in a dynamic manner. Although shown in FIG. 3 asseparate components, the functionality of the scheduling andprioritization handling entity 53 (hereinafter, the “scheduling entity53”) and the priority class and TSN setting entity 54 (hereinafter, the“TSN setting entity 54”) may be combined into a single entity.

TSN setting entity 54 is coupled between the flow controller 55 and thescheduling entity 53. The TSN setting entity 54 of the present inventionsets, for each priority class, a queue identifier and TSN for each newdata block being serviced to ensure sequence in delivery of data blocksto higher layers. The TSN is unique to each priority class and queueidentity within a high speed downlink shared channel (HS-DSCH), and isincremented for each new data block. Once a queue identifier and the TSNhave been set for a new data block, the data block is forwarded to thescheduling entity 53.

The scheduling entity 53 processes data received from the TSN settingentity 54. The scheduling entity 53 functions as a radio resourcemanager for the cell, as well as maintaining QoS requirements for theusers serviced by the UTRAN MAC-hs 50. The TSN and priority classidentifiers for the data blocks to be transmitted are forwarded to thescheduling entity 53.

In accordance with the present invention, the scheduling entity 53ensures proper prioritization of transmissions according to data flowQoS latency requirements and allows for reinitiation of failed H-ARQtransmissions that permits the greater ability to achieve QoS BlockError Rate (BLER) requirements. These abilities of the scheduling entity53 are not possible when H-ARQ processing precedes the schedulingfunction as in the prior art system of FIG. 1. The scheduling entity 53manages HS-DSCH physical resources between the H-ARQ entities 52 a, 52 band data flows according to their QoS requirements for transmissionlatency and transport channel BLER requirements. Beside the QoSparameters, the scheduling algorithm used by the scheduling entity 53may also operate according to, for example, various radio controlresource parameters such as the signal-to-interference ratio (SIR),available and rate, speed of the UE, current load of the cell and otherfactors that are well known to those of skill in the art. The schedulingentity 53 determines the data (associated with a particular UE), and theH-ARQ entities 52 a, 52 b that will service the transmission.

The transmission assigned to the H-ARQ, 52 a, 52 b is either a newtransmission, or a retransmission of data that previously was notsuccessfully delivered. Status reports from the previous transmissionsignaled between the UE H-ARQ entity 61 (shown in FIG. 4) and the UTRANH-ARQ entities 52 a, 52 b (shown in FIG. 3) are relayed to thescheduling entity 53 where it is determined whether a new orretransmission will be serviced. The UTRAN MAC-hs 50 architecturedefined by the present invention allows the scheduling entity 53, at anytime, to determine whether or not to permit new transmissions to beinitiated on an H-ARQ entity 52 a, 52 b. New transmissions may be higherpriority transmissions that need to supercede lower prioritytransmissions to achieve QoS transmission latency requirements, orre-initiation of previously failed or interrupted transmissions toachieve QoS transport channel BLER requirements.

The algorithm within the scheduling entity 53 schedules datatransmissions according to priority class. The UTRAN MAC-hs 50 of thepresent invention allows lower priority transmissions to be interruptedfor the transmission of higher priority transmissions, and provides theability to reinitiate previously failed or interrupted transmissions atany time.

The scheduling entity 53 forwards radio resource scheduling informationto the H-ARQs entities 52 a, 52 b. The scheduling entity 53 directs theH-ARQ entities 52 a, 52 b to initiate either a new transmission or aretransmission of a previous unsuccessful transmission by the particularH-ARQ entity 52 a, 52 b. The data is then forwarded to the TFC selector51 for transmission. The TFC selector 51, coupled to the H-ARQprocessors 52 a, 52 b, receives the transmissions and selects anappropriate dynamic transport format parameter for the data to betransmitted to the UE. Although shown in FIG. 3 as separate components,the functionality of the H-ARQ entities 52 a, 52 b and the TFC selector51 may be combined into a single entity.

A block diagram of a UE MAC-hs layer 60 for a UE in accordance with thepreferred embodiment of the present invention is illustrated in FIG. 4.The UE MAC-hs 60 comprises a plurality of reordering devices 62 a, 62 band an H-ARQ entity 61. Similar to the H-ARQ processor 41 describedhereinbefore with respect to the UTRAN, the UE H-ARQ entity 61 isresponsible for handling all the processes for implementing the H-ARQprotocol. Within the UE, the receiving H-ARQ entity 61 combines the softinformation from the original transmission and any subsequentretransmissions.

Within the H-ARQ protocol layer, individual transmission priorityclasses and the required sequence of delivery (TSNs) are not known.Accordingly, successful reception, transmissions are reordered accordingto their TSN by the reordering devices 62 a, 62 b. The reorderingdevices 62 a, 62 b immediately forward for processing in higher layerstransmissions following in sequence reception.

The MAC-hs process in accordance with the preferred embodiment of thepresent invention ensures that higher priority transmissions are notdelayed by processing of lower priority transmissions. Additionally,transmissions can be reinitiated at any time, thereby reducing thetransmission failure rate within the MAC-hs process. This gives thescheduling entity 53 the ability to utilize the input informationavailable to determine the best combination of transmissions to achievemaximum performance of the system, maximum use of the radio network andmaintain QoS requirements for transmission latency and BLER.

Although the elements or processes of the present invention have beendescribed as discrete hardware components, for example the schedulingentity 53 and the TSN setting entity 54, these elements will most likelybe implemented in one or more software routines or modules. It should beunderstood that the overall flow and sequence of information betweeneach process is important, not whether the process is implementedseparately or together, or in hardware or software.

Referring to FIG. 5, a method 100 for permitting transmission of higherpriority data to interrupt the transmission of lower priority data toachieve transmission latency requirements is shown. The method 100 isfor communications between a transmitter 102 (such as at the UTRAN) anda receiver 104 (such as at the UE). The method 100 assumes communicationfor a particular H-ARQ process, such as between one of the H-ARQentities 52 a, 52 b in the UTRAN and the corresponding H-ARQ entity 61in the UE.

The method 100 commences with the setting of a new data indicator (NDI)for the establishment of a new H-ARQ process (step 103). The lowerpriority data is processed (step 106) at the transmitter 102. Asaforementioned at the receiver 104, a quality check is performed wherebyan acknowledgement (ACK) is generated if the transmission is successful(i.e. received without errors) or a non-acknowledgment (NACK) isgenerated if the transmission is not successful (step 108). The ACK orNACK is sent to the transmitter 102. Steps 106 and 108 are repeateduntil the transmission is successfully received at the receiver 104, orhigher-priority data arrives at the scheduling entity (step 110) thatneeds to be scheduled to meet QoS transmission latency requirements.

If higher priority data needs to be scheduled for transmission to meettransmission latency requirements (step 110), lower priority datatransmission may be interrupted (step 112). The H-ARQ process oftransmission of the higher priority data is then commenced (step 114).Interruption of the previous data transmission is identified to thereceiver 104 by setting of the NDI. At the receiver 104, a quality checkis performed whereby an acknowledgement (ACK) is generated if thetransmission is successful or a non-acknowledgment (NACK) is generatedif the transmission is not successful (step 116). The ACK or NACK isthen sent to the transmitter 102. Steps 114 and 116 are repeated untilthe higher priority data transmission is successfully received at thereceiver 104.

Once the transmission of the higher priority data has been confirmed,the lower priority data transmission may then be reinitiated (step118).The transmission is repeated until the quality check results in an ACKbeing generated by the receiver 104 (step120). As with theaforementioned H-ARQ process, it may be necessary to retransmit thelower priority data by the transmitter 102 in response to an NACKgenerated by the receiver 104.

The method 100 of FIG. 5 is an example of scheduling of an H-ARQ processto achieve desired latency requirements for the data to be transmitted.With the proposed UTRAN MAC architecture 50 in accordance with thepresent invention, method 100 and other sequences of operation betweenthe transmitter 102 and receiver 104 are also possible to achievetransmission latency requirements.

Referring to FIG. 6, a method 200 for permitting re-initiation of failedtransmissions to achieve Block Error Rate (BLER) requirements is shown.The method 200 is for communications between a transmitter 201 (such asat the UTRAN) and a receiver 203 (such as at the UE). The method 200assumes communication for any set of H-ARQ processes associated with aUE, such as between one of the H-ARQ entities 52 a, 52 b in the UTRANand the corresponding H-ARQ entity 61 in the UE.

The method 200 commences with the processing of data for transmission(step 202) at the transmitter 201. The H-ARQ processing for the data isperformed, whereby a quality check is at the receiver 203 is performed(step 204) and an ACK or NACK is then sent to the transmitter 201. Steps202 and 204 are repeated until the data transmission is successfullyreceived at the receiver 203 or until a retransmission limit or anotherfailure criteria is reached (step 206).

In the event that a failure criterion has been reached (step 206), theUTRAN MAC architecture 50 allows for re-initiation of the failedtransmission on the H-ARQ process (steps 212 and 214). Re-initiation maybe performed after the scheduling of other pending transmissions (steps208, 210) or may proceed directly (steps 212, 214). Accordingly, it ispossible subsequent to the transmission or failure of one or more“other” transmissions. These other transmissions may be scheduled (step208) and transmitted by the transmitter 201 and the quality check isperformed and ACKs or NACKs are generated and transmitted by thereceiver 203 as appropriate (step 210).

Once the other transmissions have been successfully sent, or the failurecriteria has been reached (steps 208-210), the previously failedtransmission may be scheduled for transmission on the H-ARQ process(step 212). Re-initiation of the previous data transmission isidentified to the receiver 203 by setting of the NDI. Retransmissions ofthe data are sent and an ACK or a NACK is generated as appropriate (step214). Steps 212 and 214 are repeated until the transmission issuccessfully received at the receiver 203, or the retransmission limitor other failure criteria has been reached (step 206). The reinitiationof a previously failed transmission can be applied several times to anyparticular transmission in order to achieve BLER requirements.

While the present invention has been described in terms of the preferredembodiment, other variations which are within the scope of the inventionas outlined in the claims below will be apparent to those skilled in theart.

1. A cellular communication device, comprising: an output configured totransmit a first signal, the first signal carrying first information,said first information being stored in the cellular communication deviceafter said transmission of the first signal, a first priority valuebeing associated with the first information, the first signal being awireless signal; an input configured to receive a second signal, thesecond signal carrying second information indicating whether the firstinformation was received by a receiver, an automatic repeat request(ARQ) entity configured to receive the second information and outputthird information corresponding to the second information; and aprioritization entity configured to receive the third information fromthe ARQ entity, wherein the cellular communication device stores fourthinformation, a second priority value being associated with the fourthinformation, such that, after receiving the third information from theARQ entity, the prioritization entity selects one of said firstinformation, for retransmission from the cellular communication device,and said fourth information, for transmission from the cellularcommunication device, said selection being based on the first and secondpriority values.
 2. A cellular communication device in accordance withclaim 1, wherein the ARQ entity is a hybrid-ARQ (H-ARQ) entity.
 3. Acellular communication device in accordance with claim 1, wherein theARQ entity is associated with a first one of a plurality of protocollayers and the prioritization entity is associated with a second one ofa plurality of protocol layers, the plurality of protocol layers beingassociated with a protocol layer structure, the second one of theplurality of protocol layers being above the first one of the pluralityof protocol layers in the protocol layer structure.
 4. A cellularcommunication device in accordance with claim 1, wherein the secondinformation includes one of an acknowledgement (ACK), if the firstinformation is received by the receiver, and a non-acknowledgement(NACK), if the second information is not received by the receiver.
 5. Acellular communication device in accordance with claim 1, wherein thefirst information includes a packet, the packet having an associatedsequence number, the cellular communication device being configured toschedule the transmission of the first signal in accordance with thesequence number.
 6. A communication method, comprising: transmitting afirst signal from a cellular communication device, the first signalcarrying first information, said first information being stored in thecellular communication device after said transmission of the firstsignal, a first priority value being associated with the firstinformation, the first signal being a wireless signal; receiving asecond signal, the second signal carrying second information indicatingwhether the first information was received by a receiver; receiving thesecond information, with an automatic repeat request (ARQ) entity, andoutputting third information corresponding to the second information;receiving the third information from the ARQ entity; storing fourthinformation, a second priority value being associated with the fourthinformation; and after receiving the third information from the ARQentity, selecting one of said first information, for retransmission fromthe cellular communication device, and said fourth information, fortransmission from the cellular communication device, said selectingbeing based on the first and second priority values.
 7. A communicationmethod in accordance with claim 6, wherein the ARQ entity is ahybrid-ARQ (H-ARQ) entity.
 8. A communication method in accordance withclaim 6, wherein the ARQ entity is associated with a first one of aplurality of protocol layers and the prioritization entity is associatedwith a second one of a plurality of protocol layers, the plurality ofprotocol layers being associated with a protocol layer structure, thesecond one of the plurality of protocol layers being above the first oneof the plurality of protocol layers in the protocol layer structure. 9.A communication method in accordance with claim 6, wherein the secondinformation includes one of an acknowledgement (ACK), if the firstinformation is received by the receiver, and a non-acknowledgement(NACK), if the second information is not received by the receiver.
 10. Acommunication method in accordance with claim 6, wherein the firstinformation includes a packet, the packet having an associated sequencenumber, the communication method further including scheduling thetransmission of the first signal in accordance with the sequence number.11. A node-B comprising: a prioritization entity configured to receivefirst information; a hybred-automatic repeat request (H-ARQ) entityconfigured to receive the first information from the prioritizationentity and forward the first information; an output configured toreceive the first information and transmit a first signal carrying thefirst information to a receiver, the first signal being a wirelesssignal; an input configured to receive a second signal indicatingwhether the receiver received the first information, the H-ARQ entityreceiving the second information and supplying third information, thethird information corresponding to the second information, theprioritization entity receiving the second information from the H-ARQentity, wherein the first information is stored in the node-B after thefirst signal has been transmitted, and the node-B stores fourthinformation, the stored first information being associated with a firstpriority class and the stored fourth information being associated with asecond priority class, the prioritization entity also being configuredto select one of the stored first information, for retransmission by thenode-B, and the stored fourth information, for transmission by thenode-B, said selecting being based on the first and second priorityclasses.
 12. A node-B in accordance with claim 11, further comprising: amedium access control-high speed (MAC-hs) entity, wherein the MAC-hsentity includes the prioritization and H-ARQ entities.
 13. A node-B inaccordance with claim 11, further comprising: a transport formatcombination (TFC) entity configure to receive the first informationsupplied by the H-ARQ entity and forward the first information for saidtransmission by the output.
 14. A node-B in accordance with claim 13,wherein the H-ARQ entity supplies the first information as a data block,the TFC entity selecting a transport format for the data block, thetransport format being associated with a wideband code division multipleaccess (WCDMA) high speed downlink shared channel (HS-DSCH).
 15. Anode-B in accordance with claim 14, further comprising: a transportsequence number (TSN) setting entity, the TSN setting entity generatinga TSN, which corresponds to the data block and the first priority class.16. A node-B in accordance with claim 11, wherein the second informationincludes one of an acknowledgement (ACK), if the first information isreceived by the receiver, and a non-acknowledgement (NACK), if thesecond information is not received by the receiver.
 17. A communicationmethod, comprising: receiving, with a prioritization entity in a node-B,first information; supplying the first information to a hybrid-automaticrepeat request (H-ARQ) entity in the node-B; forwarding the firstinformation for output from the node-B; transmitting a first signalcarrying the first information from the node-B to a receiver, the firstsignal being a wireless signal; receiving a second signal, the secondsignal carrying second information indicating whether the receiverreceived the first information, receiving, with the H-ARQ entity, thesecond information; supplying third information generated by the H-ARQentity, the third information corresponding to the second information;receiving the third information with the prioritization entity, whereinthe first information is stored in the node-B after the first signal hasbeen transmitted, and the node-B storing fourth information, the storedfirst information being associated with a first priority class and thestored fourth information being associated with a second priority class;and selecting, with the prioritization entity, one of the stored firstinformation, for retransmission by the node-B, and the stored fourthinformation, for transmission by the node-B, said selecting being basedon first and second priority classes.
 18. A communication method inaccordance with claim 17, said forwarding further comprising: receiving,with a transport format combination (TFC) entity, the first informationsupplied by the H-ARQ entity; and supplying, with the TFC entity, thefirst information for said transmission from the node-B.
 19. Acommunication method in accordance with claim 18, node-B in accordancewith claim 13, wherein said forwarding the first information includesforwarding the first information as a data block, the TFC entityassigning a transport format to the data block, the transport formatbeing associated with a wideband code division multiple access (WCDMA)high speed downlink shared channel (HS-DSCH).
 20. A communication methodin accordance with claim 19, further comprising: generating a transportsequence number (TSN), the TSN corresponding to the data block and thefirst priority class.
 21. A communication method in accordance withclaim 17, wherein the second information includes one of anacknowledgement (ACK), if the first information is received by thereceiver, and a non-acknowledgement (NACK), if the second information isnot received by the receiver.